1. Field of the Invention
The present invention relates to a retractable lens (retractable lens barrel) which is retracted to reduce the length thereof when not in use, e.g., a retractable photographing (imaging) lens which is retracted into a camera body upon power being turned OFF.
2. Description of the Related Art
In a conventional zoom lens disclosed in Japanese Unexamined Patent Publications Nos. 10-161001 and 11-231201, if a lens group (position-adjustable lens group), an axial position of which is to be adjustable relative to a lens barrel, a lens frame which holds the position-adjustable lens group is screwed into an external barrel, the axial position of the position-adjustable lens group can be adjusted by rotating the lens frame relative to the external barrel.
However, according to this structure, since sufficient space allowing the position-adjustable lens group (the lens frame) to move forward and rearward for adjustment relative to the external barrel must be secured, such a space makes it difficult to reduce the length of the zoom lens to a minimum when the zoom lens is fully retracted.